The increasing demand to produce enantiomerically pure pharmaceuticals, agrochemicals, flavors, and other fine chemicals has advanced the field of asymmetric catalytic technologies. Development of efficient asymmetric metal-catalyzed transformations has played a central role for the advancement of asymmetric catalysis. In the past decades, metal-catalyzed reactions with chiral phosphine ligands have been widely utilized and advanced for variety of asymmetric transformations. Development of efficient chiral phosphorus ligands is essential for the success of asymmetric hydrogenation. Known chiral phosphorus ligands in this field include Knowles' DIPAMP [Knowles, W. S. Acc. Chem. Res. 1983, 16, 106], Kagan's DIOP [Kagan et al, J. Am. Chem. Soc. 1972, 94, 6429], Noyori's BINAP [Noyori, R. Chem. Soc. Rev. 1989, 18, 187], Burk's Duphos and BPE [Burk, M. J. et al, Organometallics 1990, 9, 2653; Burk, M. J. et al, Angew. Chem., Int. Ed. Engl. 1990, 29, 1462], Imamoto's BisP* [Imamoto, T. et al, J. Am. Chem. Soc. 1997, 119, 1799], Zhang's PennPhos [Zhang, X. et al, Angew. Chem. Int. Ed. Engl. 1999, 38, 516] and TangPhos [US2004/0229846 and Zhang, X. et al, Angew. Chem. Int. Ed. 2002, 41, 1613.], Pfizer's trichickenfootphos [WO2005/087370 and Hoge, G. et al, J. Am. Chem. Soc. 2004, 126, 5966].
More recently, families of phosphine ligands ontaining a unique dihydrobenzooxaphosphole (BOP) core which are structurally rigid, electronically and sterically tunable, and air-stable have been discovered. For example, one family of ligands (U.S. Pat. No. 9,096,626) is represented by formulas (A) and (B).

Another family of BOP ligands (U.S. Pat. No. 8,552,212) is represented by formulas C and D.

Another family of ligands (U.S. Pat. No. 8,946,418) is represented by formulas E and F.

These unique chiral BOP ligands have demonstrated superior reactivity and selectivity for various organic and asymmetric transformations including Suzuki-Miyaura cross-coupling reaction, Negishi coupling, asymmetric hydrogenation of enamides, ketones, and unfunctionalized alkenes, asymmetric proprogylation, asymmetric ketone and imine addition, asymmetric dearomative cyclization and reductive alkynone cyclization, asymmetric hydroboration and asymmetric ring-opening reactions.
Although tremendous progress has been made in the field of asymmetric hydrogenation and many efficient chiral ligands have been developed, the design of new efficient ligands continues to be important since there is no universal ligand for hydrogenation of various kinds of prochiral substrates.